Establishment and Verification of An Efficient Virus-induced Gene Silencing System in Forsythia

To understand the functional identification of large-scale genomic sequences in Forsythia, tobacco rattle virus (TRV)-mediated virus-induced gene silencing (VIGS), suitable for the plant, was explored in this study. The results showed that the TRV-mediated VIGS system could be successfully used in Forsythia for silencing the reporter gene FsPDS (Forsythia phytoene desaturase) using stem infiltration and leaf infiltration methods. All the treated plants were pruned below the injection site after 7–15 d infection; the FsPDS was silenced and typical photobleaching symptoms were observed in newly sprouted leaves at the whole-plant level. Meanwhile, this system has been successfully tested and verified through virus detection and qRT-PCR analysis. After the optimization, Forsythia magnesium chelatase subunit H (FsChlH) was silenced successfully in Forsythia using this system, resulting in yellow leaves with decreased chlorophyll content. The system was stable, highly efficient and had greater rapidity and convenience, which made it suitable to study the function of genes related to physiological pathways such as growth and development, and metabolic regulation in Forsythia.